Background: In light of the vulnerability of the developing brain, mixture risk assessment (MRA) for the evaluation of developmental neurotoxicity (DNT) should be implemented, since infants and children are co-exposed to more than one chemical at a time. One possible approach to tackle MRA could be to cluster DNT chemicals in a mixture on the basis of their mode of action (MoA) into 'similar' and 'dissimilar', but still contributing to the same adverse outcome, and anchor DNT assays to common key events (CKEs) identified in DNT-specific adverse outcome pathways (AOPs). Moreover, the use of human in vitro models, such as induced pluripotent stem cell (hiPSC)derived neuronal and glial cultures would enable mechanistic understanding of chemically-induced adverse effects, avoiding species extrapolation. Methods: HiPSC-derived neural progenitors differentiated into mixed cultures of neurons and astrocytes were used to assess the effects of acute (3 days) and repeated dose (14 days) treatments with single chemicals and in mixtures belonging to different classes (i.e., lead(II) chloride and methylmercury chloride (heavy metals), chlorpyrifos (pesticide), bisphenol A (organic compound and endocrine disrupter), valproic acid (drug), and PCB138 (persistent organic pollutant and endocrine disrupter), which are associated with cognitive deficits, including learning and memory impairment in children. Selected chemicals were grouped based on their mode of action (MoA) into 'similar' and 'dissimilar' MoA compounds and their effects on synaptogenesis, neurite outgrowth, and brain derived neurotrophic factor (BDNF) protein levels, identified as CKEs in currently available AOPs relevant to DNT, were evaluated by immunocytochemistry and high content imaging analysis. Results: Chemicals working through similar MoA (i.e., alterations of BDNF levels), at non-cytotoxic (IC 20 /100), very low toxic (IC 5), or moderately toxic (IC 20) concentrations, induce DNT effects in mixtures, as shown by increased number of neurons, impairment of neurite outgrowth and synaptogenesis (the most sensitive endpoint as confirmed by mathematical modelling) and increase of BDNF levels, to a certain extent reproducing autism-like cellular changes observed in the brain of autistic children. Conclusions: Our findings suggest that the use of human iPSC-derived mixed neuronal/glial cultures applied to a battery of assays anchored to key events of an AOP network represents a valuable approach to identify mixtures of chemicals with potential to cause learning and memory impairment in children.

-Multiple shoots of high quality were produced in vitro from nodal explants of Tectona grandis. An average of about 4 shoots/uninodal explant was obtained within 4 weeks of culture on Murashige and Skoog's (mMS) medium modified by 50% reduction in NH 4 NO 3 concentration, supplemented with benzylaminopurine (1.5 mg L −1 ); indole-3-butyric acid (0.01 mg L −1 ) and gibberellic acid (0.1 mg L −1 ). The latter was applied both in the medium and by soaking the nodal segments for 10 s. in a gibberellic acid solution of 100 mg L −1 . Hundred percent of shoots rooted cultured on modified MS medium containing IBA (0.5 mg L −1 ) and putrescine (160 mg L −1 ). Putrescine promoted both strong and highly ramified roots and fast growing shoots during the rooting phase, conditioning the plantlets for a good survival and quality. Plantlets were transferred to jiffy pots for a short acclimatization stage in greenhouse where they survived at 100%. This highly reproducible procedure can be adopted for large scale teak propagation. . La présence de la putrescine a permis d'obtenir des racines fortes et ramifiées, des pousses à croissance rapide pendant l'enracinement, donnant des plantes de qualité aptes à une bonne survie. Les plantes ont été endurcies et transférées dans des Jiffy pots pour une acclimatation brève en conditions de serre ayant pour résultat 100% de survie. Ce procédé hautement reproductible peut être adapté à grande échelle dans la propagation de teak du fait de l'efficacité du nombre de pousses obtenues (prolifération), de l'enracinement, de l'acclimatation et du bon développement des plantes. régulateurs de croissance / putrescine / enracinement / explants nodaux / acide gibbérélique

Evening primrose (Oenothera spp.) is grown commercially for its seed oil that contains gamma linolenic acid (GLA), a valuable food supplement and pharmaceutical. There is considerable interest in the potential of genetic engineering to improve yields of GLA in evening primrose, and attention has focused on the current state of tissue-culture knowledge in this species which is a prerequisite for genetic transformation. Published protocols for the regeneration of plants from leaf or cotyledon material of Oenothera spp. are available, but these prove unsatisfactory when applied to commercial cultivars used in this study. An efficient method for regenerating three commercial cultivars of evening primrose Rigel, Merlin and Vulcan was developed using thidiazuron (TDZ) as a growth regulator. Explants from one month old seedlings were cultivated in vitro; a large number of buds were induced directly from strips of leaves, cotyledons and stems when cultured on Murashige and Skoog (MS) basal medium containing TDZ and indole-butyric acid (IBA). Shoots that were excised and placed onto MS basal medium, supplemented with IBA, rooted with 85-90% efficiency. Plantlets were transferred to soil after 6-8 wk. TDZ stimulated the regeneration process, and its effects were enhanced when combined with IBA or indole-3-acetic acid (IAA). The methods developed may be a useful advance toward improvement of this oil seed crop through genetic modification.Peer reviewe

SummaryA robust Agrobacterium -mediated transformation procedure was developed for Rigel, a commercial cultivar of evening primrose, and used to deliver a cDNA encoding a ∆ 6 -desaturase from borage under the control of a cauliflower mosaic virus (CaMV) 35Spromoter. Analysis of the transformed plants demonstrated an altered profile of polyunsaturated fatty acids, with an increase in γ -linolenic acid and octadecatetraenoic acid in leaf tissues when compared with control lines.